A NASA space telescope capable of finding Earth-sized and smaller planets will draw on Australian expertise to work out which stars to focus on.

The Kepler mission, set to launch next week, aims to detect planets as they move across the face of Sun-like stars, by measuring how they dim the starlight.

But the mission wants to focus on planets orbiting stars that of a similar age, temperature and size to our sun.

To find these stars, the mission will rely on information from astro-seismologists, who measure the oscillation of stars as they expand and contract to shed light on their characteristics.

One astero-seismologist contributing to the Kepler mission is Dr Dennis Stello of the University of Sydney, who plans to watch the launch at Cape Canaveral.

He says so far astro-seismologists have been able to study oscillations in about a dozen Sun-like stars from Earth. But this is all about to change with Kepler's 95 megapixel camera - the largest to ever go in space.

"With Kepler we will get about 100,000 stars [to look at]," he says "That will of course totally revolutionise the field."

As well as helping Kepler to find Earth-like stars, astro-seismologists are interested in the examining the composition of stars and how they evolve.

Trailing Earth

Kepler will trail Earth at a distance that enables it to get away from the brightness of our planet, which would interfere with its optics.

Unlike Hubble, Kepler will look at relatively nearby stars 3000 light years away in one patch of the sky.

Hubble by contrast scans the universe looking for very faint and distant objects and would be dazzled by the stars Kepler is planning to focus on.

Theories tested

Stello says if no planets are found by Kepler then this will cast doubt on astronomers' assumptions about how planets form and mean habitable planets are rare.

"If we find planets, then the theories have been right and then it's a matter of taking the next step and investigating the planets more directly," he says.

Stello is an optimist when it comes to finding extraterrestrial life.

"There are as many stars as there are sand grains on the beaches in Australia," he says. "It seems plausible that life could exist elsewhere - even if it's under water."

But, he says any communication with other civilisations in the universe is limited by the great distances between stars, and the speed of light.